Vibrating catheter and methods of use

ABSTRACT

The invention provides a method of intravascular intervention that includes inserting a catheter comprising an extended body into a lumen within tissue of a patient, advancing the catheter to a treatment site, vibrating a proximal end of the catheter with a mechanical vibrator, and treating the treatment site while a distal end of the catheter is vibrating.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of, and priority to, U.S. Provisional Patent Application No. 61/777,394, filed Mar. 12, 2013, and also to U.S. Provisional Patent Application No. 61/777,407, filed Mar. 12, 2013, the contents of each of which are incorporated by reference.

FIELD OF THE INVENTION

The invention generally relates to systems and methods for intravascular intervention.

BACKGROUND

People die from heart attacks. Heart attacks can be caused by the slow buildup of atherosclerotic plaque inside the blood vessels. The buildup of plaque occludes the flow of blood, and thus nutrients and oxygen, to a person's tissue and brain. Sometimes chunks of the atherosclerotic plaque break away and flow through the person's blood vessels. This can lead to serious and deadly strokes and heart attacks. If the plaque buildup is extensive enough, it will fully occlude the flow of blood, forming what is called a chronic total occlusion or CTO. If a CTO is not opened up, it can be fatal.

One approach to treating a CTO is to insert an intravascular guidewire and use it to push across the CTO followed by a catheter. Unfortunately, guidewires and catheters are subject to a lot of friction. For example, where the guidewire extends through the patient's convoluted blood vessels within a catheter, at each bend, the catheter is curved, and the guidewire will typically be pushed against the wall of the catheter (i.e., the inside wall at the apex of the curve and the outside wall at the ends of the curve). The friction causes numerous problems. First, it is difficult to slide the guidewire to and through the CTO in a smooth deft motion because the friction interferes. Second, since the guidewire will not move until the friction is overcome, sometimes the guidewire resists motion and then moves forward suddenly. Unfortunately, crossing the CTO requires a lot of force but also precise control over that force.

SUMMARY

The invention provides a catheter with a vibrating mechanism attached that gives a physician great control over an intravascular procedure by keeping the catheter in motion at times when the vibrating mechanism is active with the result that the physician need not overcome a coefficient of static friction. The physician is at all times faced with a substantially uniform coefficient of dynamic friction. This amount of friction quickly becomes familiar to the physician and in fact aids the physician in gently controlling the motion of the catheter in a smooth fashion. Since static friction is removed, the catheter or guidewire does not jump forward in fits and starts with a jerky and uncontrolled motion. Additionally, the motion of the catheter draws fluid along the surface of the guidewire (e.g., blood or exogenous contrast), lubricating the surface. Fluid is drawn into the catheter, where applicable. Where the guidewire lies against a vessel wall or the plaque of a CTO, fluid is drawn into that interface, lubricating it. The lubricated, vibrating guidewire thus is able to push through the CTO in a smooth, controlled motion. This gives a physician tools for crossing a CTO, opening up a patient's blood vessels. Also, by crossing the CTO with a guidewire, a physician can then use the guidewire to take the catheter across the CTO. The catheter can be used to deliver treatments, such as angioplasty balloons or stents. In this way, a catheter of the invention can be used to resolve life-threatening plaque buildup and avoid heart attacks.

In certain aspects, the invention provides a method of intravascular intervention that includes inserting a catheter comprising an extended body into a lumen within tissue of a patient, advancing the catheter to a treatment site, vibrating a proximal end of the catheter with a mechanical vibrator, and treating the treatment site while a distal end of the catheter is vibrating. The mechanical vibrator may include a linear motor, a mass coupled to the motor by a spring, a pair of eccentric rotatable weights, a piezoelectric vibrator, an ultrasonic actuator, a non-resonant linear motor driving a mass, or a combination thereof. A distal portion of the catheter may optionally be given a low-friction surface treatment (e.g., such as a coating of PTFE on an exterior or interior surface of the catheter). In some embodiments, the method includes advancing the catheter over a guidewire to a chronic total occlusion. The catheter can be used to deliver a treatment such as a stent or balloon.

In related aspects, the invention provides a device for intravascular intervention that includes a catheter member comprising an extended body with a proximal end and a distal end, a torquer fixed to the proximal end, and a mechanical vibrator coupled to the torque. The torque may include a pin vise. The device may include a guidewire within the catheter. The catheter can be used to deliver a treatment (e.g., with a balloon or a stent).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a guidewire with catheter according to certain embodiments.

FIG. 2 shows a reinforcement coil.

FIG. 3 depicts a linear motor.

FIG. 4 illustrates a catheter with a mechanical vibrator.

FIG. 5 illustrates a catheter with mechanical vibrator with a spring.

FIG. 6 shows use of a catheter and guidewire to approach an occlusion.

FIG. 7 shows crossing an occlusion with a vibrating catheter.

DETAILED DESCRIPTION

The invention generally relates to catheters that vibrate. Systems and methods of the invention operate to decrease ambient friction around a guidewire and catheter via a vibration motion of the catheter. Additionally, the motion of the guidewire or catheter can aid in crossing a CTO.

FIG. 1 shows an system 101 including a catheter 111 and a guidewire 109 according to certain embodiments of the invention. Catheter 111 includes a proximal portion 103 that is generally outside of a patient during use and a distal portion 105 configured for insertion into a patient. Guidewire 109 also includes a proximal portion and a distal portion 105. Either catheter 111 or guidewire 109 includes at least one optical fiber for photoacoustic image as described herein. Proximal portion 103 may generally be said to define a housing area in that guidewires, endoscopes, or surgical implements may enter catheter 111 through proximal portion 103 and be housed, at least in part, within proximal portion 103.

Catheter 111 is capable of being delivered over a guidewire 109. In some embodiments (not pictured in FIG. 1), catheter 111 is an intravascular balloon catheters as is used for such procedures as balloon angioplasty, or percutaneous transluminal coronary angioplasty (PTCA). Catheter 111 generally has an elongate tubular shaft 111 with proximal portion 103 and distal portion 105, and may include one or more passages or lumens. Use of pliable materials provides flexibility or maneuverability, allowing a catheter to be guided to a treatment site in a patient's blood vessels. Preferably, a catheter of the invention has enough stiffness to allow it to be pushed to a target treatment site, and accordingly, an ability to optimize a balance of pliability versus stiffness or pushability is beneficial to medical use. In certain embodiments, catheter 111 includes a stiffening wire or coil, or a reinforcement coil, to aid in transmitting the vibration form the proximal end to the distal end. Additionally, a shaft of the catheter can be provided that is capable of transmitting torque along an axis of the shaft. Devices for cardiovascular intervention are discussed in U.S. Pat. Nos. 6,830,559; 6,074,362; and U.S. Pat. No. 5,814,061, the contents of each of which are incorporated by reference.

Catheter 111 could optionally include an angioplasty balloon 107 or other interventional device at distal portion 105 to expand or dilate blockages in blood vessels or to aid in the delivery of stents or other treatment devices. Blockages include the narrowing of the blood vessel called stenosis.

Typically, a catheter 111 will include a guidewire lumen so that the catheter may be advanced along a guidewire. Guidewire lumen in a balloon catheter is described in U.S. Pat. No. 6,022,319 to Willard. Catheter 111 may include any suitable material such as, for example, nylon, low density polyethylene, polyurethane, or polyethylene terephthalate (PET), or a combination thereof (e.g., layers or composites). An inner surface of a guidewire lumen may include features such as a silicone resin or coating or a separate inner tube made, for example, of preformed polytetrafluoroethylene (PTFE). The PTFE tube may be installed within the catheter shaft by sliding it into place and then shrinking the catheter shaft around it. This inner PTFE sleeve provides good friction characteristics to the guidewire lumen, while the balance of the catheter shaft can provide other desired qualities. Other suitable materials for use in catheter 101 or an inner tube portion thereof include high density polyethylene (HDPE) or combinations of material, for example, bonded in multiple layers.

Catheter 111 may include coaxial tubes defining separate inflation and guidewire lumens, for example, along a portion of, or an entirety of, a length of catheter 111. A plurality of lumens may be provided in parallel configuration or coaxial at one point and parallel at another, with a twisting/plunging portion to affect a transition between the parallel segment and the coaxial segment (see., e.g., U.S. Pat. No. 7,044,964). Other possible configurations include one or more of a guidewire tube or guidewire lumen disposed outside of the balloon. Or the guidewire tube may be affixed to and extend along the wall of the balloon. In some embodiments, a proximal end of guidewire 109 is mounted in a torquer device. Any torquer device may be used. For example, a handle member may be fixed onto proximal end of guidewire 109 by welding, adhesives, clamps, or other suitable means. In some embodiments, the torque device comprises a pin vise.

FIG. 2 shows a reinforcement coil 114 for transmitting vibration or torque along catheter 111. Coil 114 is preferably a material that is more rigid than a remainder of a body of catheter 111. Any suitable material may be used for coil 114 such as, for example, a plastic or polymer, a metal, or a nickel-titanium alloy or other allow. Coil 114 is depicted as a helix. Other embodiments, such as a woven mesh, are within the scope of the invention. In some embodiments, reinforcement is provided by substantially linear fibers extending along catheter 111. Preferably, catheter 111 is coupled to a mechanical vibrator. Any suitable mechanical vibrator can be used. In some embodiments, catheter 111 is connected to a linear motor.

FIG. 3 depicts a linear motor 117. Linear motor 117 is an electric motor that has an unrolled stator and unrolled rotor 119 that produces a linear force along its length. One suitable mode of operation is as a Lorentz-type actuator, in which the applied force is linearly proportional to the current and the magnetic field (F=qv×B). One exemplary motor suitable for use as linear motor is the linear motor sold under the name Dover MAB-100 Linear Motor by Danaher Motion (Wood Dale, Ill.).

Any vibratory motor can be used. For example, vibration can be induced by eccentric weight discs, piezoelectric material, linear or rotary motors, non-vibrator motors that operate against a non-uniform surface, or other means known in the art. Vibratory mechanical devices that can be modified for use with the invention are described in U.S. Pat. No. 8,336,643 to Harleman; U.S. Pat. No. 6,520,269 to Geiger; U.S. Pat. No. 5,780,958 to Strugach; and U.S. Pat. No. 4,819,740 to Warrington, the contents of which are incorporated by reference.

FIG. 4 illustrates a catheter 111 with a mechanical vibrator provided by linear motor 117 connected to pin vise 113. Operation of motor 117 imparts vibration to catheter 111. The vibration is transmitted from a proximal portion of catheter 111 to a distal portion (e.g., the distal tip). This can be aided by coil 114.

FIG. 5 illustrates a catheter 111 with mechanical vibrator that includes a linear motor 117 fixed to catheter 111, which drives a mass 202 connected via a spring 201 (partially disposed behind catheter 111 within motor 117 in the view shown in FIG. 5). A resonant spring-mass system is beneficial in that it can accomplish good inertial vibration at low power.

In some embodiments, a rotating motor drives a gear pair of eccentric rotating weights. This produces vibration in at least one direction.

In certain embodiments, a non-resonant linear motor drives a mass to produce vibration.

In some embodiments, vibration is provided by an ultrasonic actuator or transducer. This may be beneficial where high frequency vibration is desired and it provides a minimum displacement of guidewire 109.

FIGS. 6-7 show use of guidewire 109 for crossing occlusion 152 (e.g., an atherosclerotic plaque) in a blood vessel treatment site 151. As distal portion 105 of guidewire 109 approaches treatment site 151 (such as a region of a blood vessel affected by atherosclerotic plaque), a physician can optionally view site 151 on a monitor of an associated medical imaging instrument (not pictured). Using mechanical vibrator 117, a distal portion of catheter 111 is vibrated, as shown in FIG. 7. This keeps catheter 111 in motion at times when the vibrating mechanism is active with the result that the physician need not overcome a coefficient of static friction. The physician is at all times faced with a substantially uniform coefficient of dynamic friction. This amount of friction quickly becomes familiar to the physician and in fact aids the physician in gently controlling the motion of the guidewire in a smooth fashion. Since static friction is removed, guidewire 109 does not jump forward in fits and starts with a jerky and uncontrolled motion. Additionally, the motion of catheter 111 draws fluid along the surface of the guidewire (e.g., blood or exogenous contrast), lubricating the surface. The lubricated, vibrating guidewire 109 thus is able to push through the occlusion 152 in a smooth, controlled motion. This gives a physician tools for crossing occlusion 152. Guidewire 109 can be used to deliver a catheter carrying treatments, such as angioplasty balloons or stents. Intravascular procedures are described in U.S. Pat. No. 8,361,097 to Patel; U.S. Pat. No. 8,298,149 to Hastings; and U.S. Pat. No. 5,713,848 to Dubrul, the contents of each of which are incorporated by reference.

Such vascular intervention procedures by catheter are often performed in specialized clinical environments known as cath labs. The catheterized intervention procedures described herein may be performed with associated imaging procedures (e.g., using IVUS and OCT instruments). Exemplary IVUS methods are discussed in U.S. Pat. No. 8,289,284; U.S. Pat. No. 7,773,792; U.S. Pub. 2012/0271170; U.S. Pub. 2012/0265077; U.S. Pub. 2012/0226153; and U.S. Pub. 2012/0220865. OCT systems and methods are described in U.S. Pub. 2011/0152771; U.S. Pub. 2010/0220334; U.S. Pub. 2009/0043191; U.S. Pub. 2008/0291463; and U.S. Pub. 2008/0180683, the contents of each of which are hereby incorporated by reference in their entirety.

In some embodiments, guidewire 109 is used to deliver, through the use of catheter 111, an angioplasty balloon. Generally, a balloon will include a flexible, inelastic material designed to expand. By this type of expansion, a balloon may impose pressures of several atmospheres to expand the stenosis or may be used to deploy a stent. After the balloon has been expanded, it is then deflated and removed from the patient, allowing improved blood flow through the vessel. Suitable materials may include polyvinyl chloride (PVC), nylon, polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and copolyesters, polyether-polyester block copolymers, polyamides, polyurethane, poly(ether-block-amide) and the like. Balloons are described in U.S. Pat. No. 7,004,963; U.S. Pub. 2012/0071823; U.S. Pat. No. 5,820,594; and U.S. Pub. 2008/0124495, the contents of each of which are incorporated by reference. Balloon catheters are described in U.S. Pat. No. 5,779,731 and U.S. Pat. No. 5,411,016, incorporated by reference.

In some embodiments, the balloon includes artificial muscle (electro-active polymer). Electro-active polymers exhibit an ability to change dimension in response to electric stimulation. The change may be driven by electric field E or by ions. Exemplary polymers that respond to electric fields include ferroelectric polymers (commonly known polyvinylidene fluoride and nylon 11, for example), dielectric EAPs, electro-restrictive polymers such as the electro-restrictive graft elastomers and electro-viscoelastic elastomers, and liquid crystal elastomer composite materials. Ion responsive polymers include ionic polymer gels, ionomeric polymer-metal composites, conductive polymers and carbon nanotube composites. Common polymer materials such as polyethylene, polystyrene, polypropylene, etc., can be made conductive by including conductive fillers to the polymer to create current-carrying paths. Many such polymers are thermoplastic, but thermosetting materials such as epoxies, may also be employed. Suitable conductive fillers include metals and carbon, e.g., in the form of sputter coatings. Electro-active polymers are discussed in U.S. Pat. No. 7,951,186; U.S. Pat. No. 7,777,399; and U.S. Pub. 2007/0247033, the contents of each of which are incorporated by reference.

In some embodiments, guidewire 109 is used to deliver, through the use of catheter 111, a stent. Any suitable stent may be used with device 101. One exemplary device for stent is the Palmaz-Schatz stent, described, for example, in U.S. Pat. No. 4,733,665. Suitable stents are described in U.S. Pat. No. 7,491,226; U.S. Pat. No. 5,405,377; U.S. Pat. No. 5,397,355; and U.S. Pub. 2012/0136427, the contents of each of which are expressly incorporated herein by reference. Generally, a stent has a tubular body including a number of intersecting elongate struts. The struts may intersect one another along the tubular body. In a non-deployed state, the tubular body has a first diameter that allows for delivery of the stent into a lumen of a body passageway. When deployed, the stent has a second diameter and deployment of the stent causes it to exert a radially expansive force on the lumen wall. Methods of using stents are discussed in U.S. Pat. No. 6,074,362; U.S. Pat. No. 5,158,548; and U.S. Pat. No. 5,257,974, the contents of each of which are incorporated by reference. In some embodiments, stent 161 includes a shape-retaining or shape memory material such as nitinol and is self-expanding and thermally activatable within a vessel upon release. Such devices may automatically expand to a second, expanded diameter upon being released from a restraint. See, e.g., U.S. Pat. No. 5,224,953, the contents of which are incorporated herein by reference.

INCORPORATION BY REFERENCE

References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes.

EQUIVALENTS

Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof. 

What is claimed is:
 1. A method of intravascular intervention, the method comprising: inserting a catheter comprising an extended body into a lumen within tissue of a patient; advancing the catheter to a treatment site; vibrating a proximal end of the catheter with a mechanical vibrator; and treating the treatment site while a distal end of the catheter is vibrating.
 2. The method of claim 1, wherein the mechanical vibrator comprises a linear motor.
 3. The method of claim 2, wherein linear motor comprises a mass coupled to the motor by a spring.
 4. The method of claim 2, wherein the linear motor comprises a pair of eccentric rotatable weights.
 5. The method of claim 1, wherein the mechanical vibrator comprises a piezoelectric vibrator.
 6. The method of claim 1, wherein the mechanical vibrator comprises an ultrasonic actuator.
 7. The method of claim 1, wherein the mechanical vibrator comprises a non-resonant linear motor driving a mass.
 8. The method of claim 1, wherein a distal portion of the guidewire comprises a low-friction surface treatment.
 9. The method of claim 1, further comprising advancing a guidewire to a chronic total occlusion and advancing the catheter over the guidewire.
 10. The method of claim 9, wherein the catheter comprises a balloon.
 11. A device for intravascular intervention, the device comprising: a catheter member comprising an extended body with a proximal end and a distal end; a housing area at the proximal end; and a mechanical vibrator coupled to the housing area.
 12. The device of claim 11, wherein the mechanical vibrator comprises a linear motor.
 13. The device of claim 12, wherein linear motor comprises a mass coupled to the motor by a spring.
 14. The device of claim 12, wherein the linear motor comprises a pair of eccentric rotatable weights.
 15. The device of claim 11, wherein the mechanical vibrator comprises a piezoelectric vibrator.
 16. The device of claim 11, wherein the mechanical vibrator comprises an ultrasonic actuator.
 17. The device of claim 11, wherein the mechanical vibrator comprises a non-resonant linear motor driving a mass.
 18. The device of claim 11, wherein a distal portion of the catheter comprises a low-friction surface treatment.
 19. The device of claim 11, further comprising a guidewire within the catheter.
 20. The device of claim 19, wherein the catheter comprises a treatment comprising a balloon or a stent. 